Safety and efficacy of CAR-T cell targeting BCMA in patients with multiple myeloma coinfected with chronic hepatitis B virus

Background Reactivation of hepatitis B virus (HBV) infection is a well-recognized complication in patients with chronic or resolved HBV infection undergoing anticancer therapy. There is a risk of HBV reactivation after infusion of chimeric antigen receptor (CAR) T cells for patients with refractory/relapsed (R/R) multiple myeloma (MM). Methods We administered B cell maturation antigen (BCMA) CAR-T cell by infusion to nine patients with R/R MM with chronic or resolved HBV infection. Patient serum was analyzed to determine the expression of five components of HBV and the copy number of HBV DNA. HBV reactivation was defined if a patient re-exhibited hepatitis B surface antigen (HBsAg) or HBV DNA regrowth after CAR-T therapy. Results In one patient who was HBsAg-positive, no HBV reactivation was observed during the follow-up period of 9.8 months after administration of anti-HBV drugs before and after CAR-T therapy. Among eight patients with MM who had resolved HBV infection, two patients administered prophylactic anti-HBV drugs did not exhibit HBV reactivation. Of the six patients who did not use prophylactic antiviral drugs, five did not exhibit HBV reactivation, while one showed recurrence of HBsAg without detection of HBV DNA or damage to liver function. The best objective response rate was 100%, and the progression-free survival (PFS) at 12 months was of 88.89% (median PFS was not observed). Conclusions These findings showed that BCMA CAR-T cell therapy could be used in patients with R/R MM with chronic or resolved HBV infection and that antiviral drugs should be administered in these patients during CAR-T cell therapy.